1. Field of the Invention
This invention relates to a magnetic head which employs two magnetoresistive elements having a magnetoresistive effect such that their resistance values vary with an external magnetic field intensity, a device for reading out magnetically recorded information on a magnetic recording medium by the use of the magnetic head, and a device for detecting the position of a magnetization transition of recorded pattern on the magnetic recording medium and the direction of relative movement of the magnetic head with respect to the magnetic recording medium.
2. Description of the Prior Art
Conventional magnetic heads are usually induction-type. The output from the induction type magnetic head is dependent upon the speed of magnetic field variations, that is, the relative velocity of the magnetic head with respect to a magnetic recording medium. In the case of reproducing a digital magnetic record by the induction type magnetic head, processing such, for example, as differentiation of the output waveform to detect its zero cross point is needed for detecting the peak positions of the output waveform since the reproduced information exists in correspondence to the peak position of the output waveform. Further, in the case of a positioning control employing the induction type magnetic head and a magnetic record on a magnetic recording medium, variations in the relative speed between the magnetic head and the magnetic recording medium results in an unstable output and, when the magnetic head and the recording medium stand still relative to each other, it is entirely impossible to detect whether or not the information lies at the position corresponding to the peak of the output waveform.
On the other hand, a magnetoresistive element or semiconductor element, which changes its resistance value in response to a magnetic field, produces an output corresponding to the magnetic field and, in this case, the variation of the resistance value is not dependent upon the relative velocity between the recording medium and the magnetic head. Accordingly, this element is suitable for use in the abovesaid positioning control. With a conventional magnetic head employing a single magnetoresistive element, however, even if linearization of the output can be easily achieved since the position of magnetization transition on the magnetic recording medium is detected as the peak position of the output waveform, it is necessary to detect the peak position of the output waveform by differentiation for reproducing a position signal. And such a conventional magnetic head is not suited for use in the detection of a steady state location on the recording medium, and cannot provide information on the direction of movement.